Conventionally, as a power system which supplies DC power to an electronic appliance such as an amplifier for audio which dislikes contamination of noises from outside, there was used such a system that, after accepting the supply of alternate power, which would be rectified, obtained a power in the shape of rectified wave, and obtained a direct current with ripples as little as possible by means of a smoothing capacitor, a ripple filter circuit, and a stabilizing circuit, etc., and outputted this.
However, even if the above described power system was used, any DC power completely without ripples was not obtainable, and in the case when such a DC power was supplied to the above described amplifier for audio, noise (hum) due to the ripples was generated by the amplifier for audio.
Taking the above described background into consideration, in recent years, amplifiers for audio, etc., which are supplied with power from batteries (that is secondary batteries) with huge capacities, have been proposed, and some have already been introduced for practical use.
However, an amplifier for audio, etc., powered by a battery with a huge capacity, which is large in size, is inconvenient in terms of transportability and installation, and in addition when the battery is discharged and the supply of power has been stopped, it will become necessary for the battery to be charged over a comparatively long hours, and during the period the amplifier for audio, and moreover, any audio equipment itself will not become unusable.
The present invention has been accomplished, by contemplating the above described backgrounds, and the purpose thereof is to provide a power system or the like which does not become very large in terms of size, and in addition does not halt any supply of DC power due to charging after discharge.